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Memory upgrade compatibility list for iMac 2019-2020

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The first post of this thread is a WikiPost and can be edited by anyone with the appropiate permissions. Your edits will be public.
pldelisle said:
I’d upgrade directly to 64 GB. You have to pick the same brand and same capacity for all your memory modules. It also have to be the same DRAM chip manufacturer. With Crucial and Samsung it’s more easy than the others since you know it’s going to be Micron or Samsung chips. Not the same for OWC which buy DRAM chips from different manufacturers.
Click to expand...

Thanks. I don't know that I actually need more than 32GB for what I am doing and would prefer not to spend the extra $$ if not necessary. I had planned to buy from OWC as I've had good success with them on other computers, but I guess I'll just pay a little more for Crucial just in case I need more down the road as the 2020 seems to be more picky than prior models.

pldelisle said:
Modules are in pair in slots 1-3 and 2-4. Don’t mix. Rule #1.
Click to expand...

That's what I thought, but what is this about?
#147
 
jazzer15 said:
Thanks. I don't know that I actually need more than 32GB for what I am doing and would prefer not to spend the extra $$ if not necessary. I had planned to buy from OWC as I've had good success with them on other computers, but I guess I'll just pay a little more for Crucial just in case I need more down the road as the 2020 seems to be more picky than prior models.
Click to expand...
Good decision. Pretty sure at 99.999% it will work in the future because it will be the same ICs On the memory module.

jazzer15 said:
That's what I thought, but what is this about?
Click to expand...
The rules are pretty explicits but the mixing is at your own risk. If it was my money I wouldn‘t try to mix anything. Just buy 2x16 GB Crucial RAM for Mac (see models in first post of this thread) and everything will be alright.
 
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371E76AD-9EE6-423A-94E7-FE5691263371.jpeg25D2FEEE-2595-4D1F-9750-94D4841CAB0B.jpegFB32EAD2-8F63-4D8E-AA54-3918C3C23EEA.jpeg
32GB Crucial CT2K16G4S266M


Today I received another 32GB kit from Crucial, I already had the same kit ..but now its complete for me.
So this test is with 64GB ram, and I like the Multiscore ; 9010


Greetz,
 
Ran across this on the web. Can't find any such document regarding Apple computers. Is this how dual channel works or supposed to work on these machines? As in if we set it up this way, it should be at full speed and dual channel? Skip down to dual channel.

www.intel.com

Intel Support

Intel® Customer Support home page
www.intel.com www.intel.com
 
Can they make RAM options any more confusing? What is the difference between item 1 and 3 in the attached other than the price and the fact that only the more expensive one seems to currently be in stock?
 

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  • Screen Shot 2020-09-01 at 3.54.28 PM.png
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pldelisle said:
Try Amazon ?
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Out of stock there to. The Crucial site links now to NewEgg (shipping from China - 10-32 days) and Micro Center at $170. I placed an order earlier on Amazon when it was indicating they would be getting some in by September 8, so I'll see what happens. I guess however many units they are are expecting to receive are already spoken for now. I may have gotten in under the wire. It was after I placed the order that I saw the single SODIMM and got confused, but I actually ordered the right thing.
 
jazzer15 said:
Out of stock there to. The Crucial site links now to NewEgg (shipping from China - 10-32 days) and Micro Center at $170. I placed an order earlier on Amazon when it was indicating they would be getting some in by September 8, so I'll see what happens. I guess however many units they are are expecting to receive are already spoken for now. I may have gotten in under the wire. It was after I placed the order that I saw the single SODIMM and got confused, but I actually ordered the right thing.
Click to expand...
I believe the prices for Apple's RAM upgrade make Crucial very happy right now ...!
 
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iMac 2020 ( i5, 5300 ) is working great with HyperX Impact 2x16GB ( Hynix CRJ’s chips )

My post from other thread with Geekbench 5 scores:

forums.macrumors.com

Memory upgrade troubleshooting in 2020 27-inch iMacs

Base iMac 2020 Is working great with HyperX Impact 2x16GB. ( Hynix CRJ’s chips ). I need to say that I’m pretty happy with Radeon Pro 5300. This GPU is really close to Desktop 5500XT 4GB. Geekbench 5 scores:
forums.macrumors.com forums.macrumors.com
 
Can anyone confirm whether or not the CT2K32G4FD8266 works. It is available locally from Amazon. The Crucial website says it does not. I cannot find the CT2K32G4S266M anywhere in Australia. I saw a few who said they bought it or thought about buying it, but haven't heard if it turned out to be compatible.
 
When filtering all the Crucial memory, I get down to this :

Screen Shot 2020-09-02 at 8.40.38 PM.png


CT2K32G4SFD8266 seems to be the one equivalent to the Mac certified kit.

www.amazon.com.au

Crucial 64GB Kit (32GBx2) DDR4 2666 MT/S CL19 SODIMM 260-Pin Memory - CT2K32G4SFD8266

There’s an easy cure for a slow computer: more memory. Designed to help your system run faster and smoother, Crucial Laptop Memory is one of the easiest and most affordable ways to improve your system’s performance. Load programs faster. Increase responsiveness. Run data-intensive applications wi...
www.amazon.com.au
 
pldelisle said:
When filtering all the Crucial memory, I get down to this :

View attachment 949755

CT2K32G4SFD8266 seems to be the one equivalent to the Mac certified kit.

www.amazon.com.au

Crucial 64GB Kit (32GBx2) DDR4 2666 MT/S CL19 SODIMM 260-Pin Memory - CT2K32G4SFD8266

There’s an easy cure for a slow computer: more memory. Designed to help your system run faster and smoother, Crucial Laptop Memory is one of the easiest and most affordable ways to improve your system’s performance. Load programs faster. Increase responsiveness. Run data-intensive applications wi...
www.amazon.com.au
Click to expand...

So I just read through this whole thread but I lost track. I saw the post which said the only difference here is in materials used to comply with Apple guidelines, but has anyone actually put the version without M in their iMac and confirmed they work normally?

On Amazon Germany the M version costs 323€ while the other one is 237€. Since I want to get two of the kits (4x32GB) the difference is significant. Thanks!
 
Bertel said:
"So I just read through this whole thread but I lost track. I saw the post which said the only difference here is in materials used to comply with Apple guidelines, but has anyone actually put the version without M in their iMac and confirmed they work normally?"



I have ordered the (2x32GB) CT2K32G4SFD8266 from Amazon Australia, and it is in route, so I hope to have it installed sometime next week and will report. Another person told me it worked fine in theirs.
Click to expand...
 
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The only difference I see is the materials and PC Speed says PC4-21300 for the CT2K32G4S266M and PC speed - PC4-25600 for the CT2K32G4SFD8266.
 
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jiminoz said:
I have ordered the (2x32GB) CT2K32G4SFD8266 from Amazon Australia, and it is in route, so I hope to have it installed sometime next week and will report. Another person told me it worked fine in theirs.
Click to expand...
The sticks are virtually identical. I can’t see why it wouldn’t work. Of course Crucial won’t back you up in case of problem because « there are certified sticks » but you will never have problem with crucial memory.
 
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pldelisle said:
The sticks are virtually identical. I can’t see why it wouldn’t work. Of course Crucial won’t back you up in case of problem because « there are certified sticks » but you will never have problem with crucial memory.
Click to expand...


I received the (2x32GB) CT2K32G4SFD8266 today and they work perfectly. Previously, I had two sets of 2x16 OWC ram, but they were not identical, so I assume I did not have dual channel memory. I had expected to see some improvement in benchmark scores, but they are virtually identical in Geekbench and Novabench. I have a return authorisation from OWC, so I will send them back, but perhaps I was hasty in buying the somewhat more expensive Crucial memory.
 
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jiminoz said:
I received the (2x32GB) CT2K32G4SFD8266 today and they work perfectly. Previously, I had two sets of 2x16 OWC ram, but they were not identical, so I assume I did not have dual channel memory. I had expected to see some improvement in benchmark scores, but they are virtually identical in Geekbench and Novabench. I have a return authorisation from OWC, so I will send them back, but perhaps I was hasty in buying the somewhat more expensive Crucial memory.
Click to expand...
Thanks for reporting, I'll be ordering the Crucial then. OWC seems quite hard to get in Europe and the Crucial is a bit cheaper anyway.
 
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